The related technologies indicate that in some applications, for example, in heat pump application in low temperature environment, the decrease of the evaporating temperature will lead to the reduce of the capacity of a refrigeration cycle system, and the performance of an ordinary single-stage rotary compressor becomes too worse to use. If a solution of large-capacity enhanced vapor injection is adopted, the capacity of the refrigeration cycle system can be improved effectively, but an ordinary high displacement double-cylinder enhanced vapor injection rotary compressor still performs a double-cylinder operation in case of a small compression load, which makes the running efficiency worse.